The invention relates to the testing of cigarettes or other rod-shaped articles of the tobacco processing industry (hereinafter called cigarettes or filter cigarettes for short), and more particularly to improvements in apparatus for testing the end portions of cigarettes. Still more particularly, the invention relates to improvements in apparatus which can be utilized with advantage to detect cigarettes wherein the end portions contain unsatisfactory (especially insufficient) quantities of tobacco and/or other fibrous material.
Commonly owned U.S. Pat. No. 3,951,267 (granted Apr. 20, 1976 to Joachim Reuland for "Apparatus for testing the end portions of cigarettes or the like") discloses an apparatus which is used to determine the mass of tobacco shreds in the end portions of rod-like tobacco filters or filter cigarettes. The patented apparatus employs a conveyor which transports a succession of cigarettes sideways in order to advance the end portions of fillers of successive cigarettes between or past two electrodes forming part of a capacitor which is in circuit with a source of high-frequency voltage. The source establishes a high-frequency field in the path of successive end portions so that the end portions influence the field to an extent which is indicative of the mass of tobacco in the thus tested ends. The influence of successive end portions upon the field is evaluated by a circuit which generates signals serving to segregate cigarettes with fillers having defective ends. The patented apparatus can be used for the testing of all kinds of rod-shaped articles of the tobacco processing industry including plain or filter tipped cigarettes, cigars or cigarillos as well as filter rod sections of the type used in filter tipping machines for the production of filter cigarettes or like rod-shaped articles. In comparison with mechanical testing apparatus which employ pins or other components designed to penetrate into or to bear against the tobacco particles at the ends of cigarettes, the patented apparatus exhibits the advantage that it need not employ moving parts in order to carry out the actual testing operation. This enables the patented apparatus to test rod-shaped articles of the tobacco processing industry at the rate at which the articles are turned out by a modern high-speed production line.